AUSTIN, Texas (AP) Austin authorities shot and killed a man who they say opened fire on the Mexican Consulate, city police headquarters and other downtown buildings early Friday morning.

Police response to the shooting, which was reported at 2:22 a.m. Friday, was slowed by the discovery of an apparent explosive device in the suspect's vehicle, Assistant Police Chief Raul Munguia said at a news conference.

"An officer outside the building saw the suspect, fired at the suspect, the suspect went down," Munguia said.

When officers approached, they saw the device inside the vehicle and began to drag him away from it, Munguia said. But they then noticed the suspect wearing a vest and, fearing that it may be rigged to explode, left the man and retreated for cover. Munguia did not provide additional details on the garment.

A bomb squad was called to the scene. Officers also were searching the suspect's residence in the Austin area for explosive devices, but police did not immediately confirm whether explosives were found either downtown or at the residence.

Munguia said the unidentified man also shot at the U.S. courthouse. No injuries were reported from the gunfire there or at other locations. Some bullets hit police headquarters.

The shootings happened near the popular Sixth Street entertainment district, where bars close at 2 a.m. The governor's mansion is also a few blocks away; it's not known whether Gov. Rick Perry was there at the time.

Police are trying to determine a motive for the gunfire, which shut down a stretch of Interstate 35 for hours. The interstate later reopened but several blocks downtown remained closed to the public.